The Invisibles are a splinter operation of the BPI who, for reasons, find it necessary to stay out of the public eye. They live in residential zones at the BPI Headquarters. The Invisibles' reason for being delegated to this group can be obvious, like Urie, but some, like Jonah here, are more subtle.
Jonah's eyes are cursed in to always see "The Truth". This has several ramifications. He's immune to Gorgons' Gaze, which is why he's partnered with Urie, Marie inexplicibly has a gangster following her around, and Willit... Willit terrifies Jonah to the point of hysterics. He can't even explain WHAT Willit looks like, but it's infathomably horrible. While this seems useful, it also forces Jonah to be guided around everywhere he goes. If there's a locked door and Jonah isn't personally holding the key, it looks like a blank wall, as an example. His extrasensory sight has ironically rendered him practically blind.